High voltage cable termination



Jan. 27, 1970- H. A. WILLIAMS ETAL 3 5 I HIGH VOLTAGE CABLE TERMINATIONOriginal Filed Oct. 28, 1963 CONTROL HIGH UNIT T VOLTAGE1 j AIR W PUMP hI. M I

f V26 I PAINT I PUMP 9 I BRA/D z -m saz/ir/ou United States Patent3,492,409 HIGH VOLTAGE CABLE TERMINATION Herschel A. Williams,Manchester, Tenn., and Edward W. Drum, Indianapolis, Ind., assignors toRansburg Electro-Coating Corp., a corporation of Indiana Originalapplication Oct. 28, 1963, Ser. No. 319,142, now Patent No. 3,292,860,dated Dec. 20, 1966. Divided and this application Oct. 6, 1966, Ser. No.584,709

Int. Cl. H02g 15/02, 15/08; H01r 13/54 US. Cl. 174-78 9 Claims ABSTRACTOF THE DISCLOSURE A high voltage cable having a conductive braid sheathsecured to a terminal fitting sleeve with a conductive cement providingelectrical continuity and a structural cement providing a physicalconnection.

This application is a division of Williams et al., Ser. No. 319,142,filed Oct. 28, 1963, now Patent 3,292,860.

This invention relates to a high voltage cable termination, particularlyfor securely anchoring a cable to a de' vice, as an electrostatic spraygun.

A high voltage cable, such as that used with electrostatic coatingequipment, has a central body of insulating material, as polyethylene,with a conductor in the center thereof. Surrounding the polyethylenebody is a woven conductive covering which is grounded. A thin sheath ofinsulating material surrounds the woven conductive covering. A metallicelement surrounds the insulating sheath providing physical protectionfor the cable. It is necessary to attach the cable securely to thedevice with which it is used, with a good electrical connection at leastto the woven conductive covering and a mechanical connection to anchorthe cable securely.

A feature of the invention is that the high voltage cable has a terminalfitting including a sleeve with a bore through which the cable extends.The braid of the cable is electrically connected to the sleeve with aconductive cement and the cable is securely anchored in the fitting witha structural cement.

Further features and advantages of the invention will readily beapparent from thefollowing specification and from the drawings, inwhich:

FIGURE 1 is a diagrammatic illustration of a system embodying theinvention; and

FIGURE 2 is an enlarged fragmentary section through the cable fitting.

In a hand spray gun the various connecting cables or hoses, as forpaint, air and high voltage, should enter the gun in such a manner thatthey do not destroy the balance or maneuverability of the gun. It isgenerally desirable that they enter through the rear of the gun andpreferably through the base of the handle. This presents certainproblems in isolating the coating material passage from the high voltagecircuit.

In the system of FIGURE 1 of the drawings, spray gun 5 has a barrelportion 6 with a spray 7 of particles of coating material emitted fromthe front thereof and directed generally toward articles to be coated,carried by a grounded conveyor (not shown). A spray charging electrode 8is connected through a circuit in the gun (not shown) and high voltagecable 9 with a source 10 of high voltage, establishing a high intensityelectrostatic field extending from the electrode to the groundedarticles. The spray particles acquire a charge and are attracted to anddeposited on the grounded articles. A coating material conduit 11, ofinsulating material, is connected with the gun near the front of thebarrel and supplies coating material from a pump 12 through a valve 13.Air pump 3,492,409 Patented Jan. 27, 1970 14 is connected through hose15 with an air inlet at the rear of the barrel 6.

A conductive support 17 extends downwardly from the rear of barrel 6through a carrier ring 18 on which the gun is mounted. Valve 13 ismounted on gun support 17.

A control unit 19, shown diagrammatically, may be provided to controlvalve 13, high voltage source 10 and air pump 14. The details of thecontrol unit are not important to the present invention. It issufficient to point out that paint valve 13 should not be opened exceptwhen both air and high voltage are available.

A high voltage circuit housing has a first leg which extends through thebore of barrel 6 and a second leg 21, at right angles to the first leg,which extends through steel support tube 17. The high voltage housing isof a suitable high dielectric material, as polyethylene.

The high voltage cable, best seen in FIGURE 2, has an outer conductiveand protective member 23 surrounding a neoprene sheath 24. Within thesheath is a braid 25 of conductive material which overlies thepolyethylene insulating body 26. Insulating body 26 and inner conductor27 extend through leg 21 of the high voltage housing. The fitting whichis secured to the cable and provides for attachment of the cable to thelower end of support 17, includes a ferrule 28 and a threaded ring 29.Ferrule 28 has bore portions 28a and 28b of differing diameter withshoulder 28c between. The outer conductive member is fastened tonarrower bore portion 28 11. It is important that a good electricalconnection be formed between the braid and the ferrule, to ground theapparatus through the inner braid which is grounded at the high voltagepower supply 10. Thus, support 17 and coating material valve 13(FIGURE 1) are electrically grounded.

A quantity of conductive epoxy cement 31 connects thebraid 25 andferrule. The remainder of the recess between the ferrule and the cableis filled with a body 32 of structural epoxy cement which secures andretains the braid and bears against shoulder 28c, locking the cable andferrule together.

We claim:

1. In a high voltage electrical device having a high voltage cable withinner conductor, a layer of insulating material and a conductive sheath,a connecting fitting, comprising:

a conductive sleeve having a bore through which the cable extends intosaid device, said bore having an outer portion and an inner portion;

a body of conductive cement between said conductive sheath and thesleeve in the outer portion of the bore; and

a body of structural cement between the cable and the sleeve in theinner portion of the bore, securing the cable against movement outwardly,of the fitting.

2. The cable and cable fitting of claim 1 wherein said body ofstructural cement and said sleeve have interlocking surfaces.

3. The cable and cable fitting of claim 2 wherein the outer bore portionis narrower than the inner bore portion, with a wall surface joining theinner walls of said bore portions, said body of structural cementbearing against said wall surface.

4. The cable and cable fitting of claim 3 wherein said wall surface is ashoulder generally perpendicular to each bore portion.

5. The cable and cable fitting of claim 1 wherein said cable has aprotective covering outside said conductive sheath which terminatesshort of the body of conductive cement between the conductive 'sheathand fitting.

6. The cable and cable fitting of claim 5 wherein said protectivecovering includes an insulating sheath surrounded by a conductiveelement.

7. In combination, the high voltage cable and the high References Citedvoltage cable fitting of claim 1 and an electrostatic spray UNITEDSTATES PATENTS gun connected to the high voltage cable and to the high 2043 341 6/1936 Turechek 174 76 X g g l 215201705 8/1950 Wittlinger 17435.1

. e combination of clalm 7, wherein the fitting 5 3117298 1/1964Grunwald 338 312 further includes a ring securing the fitting to thegun, 3367578 l 2/1968 Juvinan et Q'ZZT; the ring including a flange andthe sleeve including a 2:402:049 6/1946 lngans X flange which engageswith the flange of the ring whereby the cable is attached to the gun.LARAMIE E. ASKIN, Primary Examiner 9. The combination of claim 8,wherein the ring is 10 threaded and is turned onto a threaded conductivesupport of the electrostatic spray gun. 174-78; 339-89; 23915

